1. Field of the Invention
The present invention relates to an organic light emitting diode (OLED) display device and a method of fabricating the same.
2. Description of the Related Art
Among flat panel display devices, because an OLED display device has a fast response time (e.g., 1 ms or less), a low power consumption, a self-emission characteristic and a wide viewing angle, it can be utilized as a moving picture display medium regardless of the size of the device. Further, the OLED display device can be fabricated at a low temperature by a simple process based on conventional semiconductor processing technology, so that it has attracted attention as a next generation flat panel display device.
An OLED display device may include a polymer device formed by a wet etching process or a small molecular device formed by a deposition process according to the material and process used to manufacture an organic light emitting diode.
An inkjet printing method for patterning a polymer or small molecular emitting layer has disadvantages in that materials suitable for forming organic layers, other than the emitting layer, are limited, and a structure for inkjet printing should be formed on a substrate. A deposition method for patterning an emitting layer is difficult to be applied in the formation of a large-sized device due to the use of a metal mask.
Laser induced thermal imaging (LITI) has been recently developed as an alternative to the above-described patterning methods.
LITI is a method which converts laser emitted from a light source into heat energy and forms a pattern using the heat energy. For this method, a donor substrate having a transfer layer, a light source, and another substrate as an object of the deposition are required.
According to a conventional method of fabricating an OLED display device, when a transfer layer is transferred onto a substrate having a pixel defining layer using LITI, the transfer layer cannot uniformly cover an edge of the substrate, because of a step difference between the pixel defining layer and the substrate. Thus, after a patterning process, an edge-open region is formed in a region which does not have the transfer layer, so that a patterning defect is generated at a boundary region of a pixel portion.